Genetic testing to help understand an uncertain result

Testing family members to help understand an uncertain genetic test result

This handout has general information about genetic testing for family members when someone in the family has an uncertain genetic test result. This type of testing is most often done on biological parents to help understand an uncertain result in their child. Sometimes, depending on the situation, other family members may also be offered testing. This type of testing is not offered for all uncertain genetic test results.

An uncertain genetic test result is also called a variant of uncertain significance (VUS).

Genetic variants

Genetic variants are the differences in our genetic instructions that make us different from each other.

Most genetic variants do not cause any health problems, but some do. Sometimes there is not enough information known about a specific genetic variant to say if it will cause health problems. This is called a variant of uncertain significance, or a VUS.

If genetic testing found a VUS (in other words, if a genetic test had an uncertain result), that person’s family members may be tested to help understand the VUS.

How testing family members can help clarify an uncertain genetic test result

Testing family members for a VUS can:

• Find out if a VUS was passed down from a parent. This is called an inherited variant.
• Find out if a VUS happened for the first time in the person with the uncertain result. This is called a “de novo” variant (de novo is Latin for “new”). Both biological parents need to be tested to determine if a variant is de novo.
• Find out if a VUS follows the pattern of inheritance for a specific health concern or genetic condition. In this case, additional family members may be offered testing.

Knowing if another family member has the same VUS may help understand whether the variant is benign (not disease-causing) or pathogenic (disease-causing). When the genetics team is able to determine whether a VUS is benign or pathogenic, this is called reclassifying the VUS. However, more information may be needed to reclassify the VUS, like:

• If the family member being tested has the same genetic condition or health concerns as the person with the VUS.
• If everyone with a pathogenic variant is expected to develop symptoms.

After testing family members, the result may remain uncertain (still a VUS). The test result may also not change any treatment or management of a health concern or genetic condition.

For the genetics team to reclassify a VUS, it needs to meet specific criteria, even if the variant is found in a gene that could explain someone's symptoms. If this happens, your healthcare team will talk with you about further testing and research options that may be available.

Testing biological parents when a child has an uncertain result

When testing the biological parents of a child who has had an uncertain result, both parents may not be available or willing to do this type of genetic testing. It can still be helpful for only one biological parent to have testing.

If both biological parents provide a sample for testing, the laboratory doesn’t always do their tests at the same time. If testing happens one at a time and the first parent tested has the VUS, the second parent’s genetic sample may not be tested.

Getting accurate and relevant results for this type of family testing depends on knowing the correct relationships between family members. Because of this, in some situations, the laboratory may check to see if both parents are the child’s biological parents. If this is a concern for you, please talk to your genetics healthcare team.

Eligibility

Not everyone is eligible for genetic testing. If you are eligible, your healthcare team will decide which type of genetic testing will be best for you. Genetic testing is optional. Your healthcare team is here to answer your questions and help you make a decision that is right for you and your family.

Learn more about genetic testing in Alberta.

To see this information online and learn more, visit MyHealth.Alberta.ca/health/aftercareinformation/pages/conditions.aspx?hwid=ab_genetictest_uncertain_result_inst.

For 24/7 nurse advice and general health information call Health Link at 811.

Current as of: March 15, 2026

Author: Clinical and Metabolic Genetics Program, Alberta Health Services

This material is not a substitute for the advice of a qualified health professional. This material is intended for general information only and is provided on an "as is", "where is" basis. Although reasonable efforts were made to confirm the accuracy of the information, Alberta Health Services does not make any representation or warranty, express, implied or statutory, as to the accuracy, reliability, completeness, applicability or fitness for a particular purpose of such information. Alberta Health Services expressly disclaims all liability for the use of these materials, and for any claims, actions, demands or suits arising from such use.